Time-delay circuit controller



Oct. Il, 1949. J, 0, MQORHEAD 2,484,112

TIME-DELAY CIRCUIT CONTROLLER Filed sepa. 29, 1944 Patented oct. 11, 1949 TIME -DELAY CIRCUIT CONTROLLER John O. Moorhead. Attleboro, Mass., assignor to Metals and Controls Corporation, Attleboro, Mass., a. corporation ot Massachusetts Application September 29, 1944, Serial No. 556,349

4 Claims. (Cl. 2011-88) 1 This invention relates to time-delay circuit controllers, and more specically to a controller of this class particularly adapted for controlling v an electron tube circuit.

Among the several objects of the invention may be noted the provision of an improved timedelay controller for closing a first circuit a substantially predetermined time interval after the closing of a second circuit; the provision of a controller of the class described particularly adapted for closing the plate or anode circuit of an electron tube a substantially predetermined time interval after the closing of its filament or cathode circuit; the provision of a controller of this class which is automatically resetting; and the provision of a controller such as described which is economical to manufacture and reliable in operation. Other objects will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which Will be exemplied in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which is i1- lustrated one of various possible embodiments of the invention,

Fig. 1 is a front elevation of a controller made according to the present invention;

Fig. 2 is a side elevation of the Fig. 1 controller; and

Fig. 3 is a diagrammatic representation of an electron tube circuit utilizing the Fig. 1 controller.

Similar reference characters designate corresponding parts throughout the several Views of the drawings.

The controller of the present invention includes a thermostatically controlled ambient compensated switch I including a thermostat which has two thermostatic elements, 3 and 5, mounted at their edges and attached centrally to a post 1. Discs 3 and 5 are made so that they tend to snap in opposite directions upon a given temperature change. Such a thermostatic control is shown in Wilson Patent 2,203,558. The tendency of disc 3 to move upon ambient temperature changes is counteracted by the tendency of disc 5 to move in the opposite direction upon such temperature change. A heater 9 is located adjacent disc 5 locally to heat that disc at a more rapid rate than disc 3.

Post 1 has a projecting knob II which abuts the head I3 of a post I5 constructed of electrically non-conductive material. Head I3 of post I5 abuts one side of a. contact carrying strip I1, and a shoulder I6 on post I5 abuts the other side-of strip I1. Strip I1 is mounted at one end on a post I9 and carries at its opposite end, on opposite sides, contacts 2| and 23. Mounted on the case 25 of thermostatic switch I is a stationary contact 21. Contact 2I, is located to cooperate with contact 21. Also attached to case 25 is a bracket 29 carrying a contact 3l. Contact 23 is located to cooperate with contact 3|. Strip Il forms the contactor of .a two-pole double-throw switch and is movable between a rst position wherein contacts 2l and 21 are engaged and a second position wherein contacts 23 and 3l are engaged.

A strip 33y forming the contactor of a relaycontrolled switch is pivotally mounted at 35 on a post 36 and carries on its opposite end a contact 31. A shoulder 39 of electrically non-conductive material attached to an armature 41, bears against one side of strip 33. Contact 31 has a. stationary cooperating contact 4I mounted on a bracket 43. Located in the arm of bracket 43 is a. magnetic relay coil 45 controlling armature 41. Shoulder 39 on armature 41 abuts post I5. A spring 49 biases armature 41 away from magnetic coil 45. A supporting shelf 5I is located above and is attached to coil 45. Shelf 5I is also attached through posts 53 to the case 25 of thermostatic switch I. Thermostatic switch I is mounted on a base 55 through posts 51. Contact terminals or tines 59 are likewise mounted on base 55 and electrically connected as shown in Fig. 3. A cover 6I is desirably provided for the relay.

The way in which the controller is connected in an electron tube circuit is diagrammed in Fig. 3. A tube 63 having a plate or anode 65 and a lament `or cathode 61 is illustrated. The plate 65 is electrically connected through a tine 59 to stationary contact 4l. Movable contact 31 is connected through another tine 59 in the plate circuit. A third tine 59 connects one side of the lament or cathode circuit in shunt to movable contact arm I1. A fourth tine connects the other side of the lament to heater 9 and thence to stationary contact 21, and also to the magnetic coil 45. The other end of the magnetic coil is connected to stationary contact 3I.

The operation of the device is as follows: Discs 3 and 5 are constructed so that when the pair is in its stable position the discs are bowed as shown in solid lines in Fig. 3. and when disc 5 is heated by heater 8 they snap to the position shown in dotted lin'es in Fig. 3. If switch Il in the filament circuit be closed so' that current passes to illament 61, it will also pass through the shunt circuit in the relay to strip I1, to contact 2|, to contact 21, to heater 8, and back to the line. Heater 9 will thereupon heat disc 5 faster than disc 3, and disc will thereupon overpower disc 3 and snap the pair to the position shown in dotted lines in Fig. 3. It will be noted that up to this point the circuit to the plate 55 has been open.

Snapping of the thermostatic discs to the dotted line position in Fig. 3 will drive the end II of post 1 against the head I3 of post I5. This will force post I5 upwardly against the bias of spring 49. Strip I1 will be pulled upward by head I3 and by its own normal bias until contacts 23 and 3| are brought together. This will close a circuit across the lament circuit through strip I1, contact 23, contact 3|, bracket 43, holding coil 45, then back to the line. Simultaneously the circuit through heater 9 has been broken.

The movement of post I5, described above, has

by moving shoulder l31| pushed strip 33 upward, but the gap between contacts 31 and 4| is larger than the gap between contacts 23 and 3| so that the movement of post I5 does not bring contacts 31 and 4| together. Closing the circuit to the magnetic coil 45 causes it to attract the armature 41. Shoulder 39 thereupon pulls strip 33 farther upward bringing contacts 31 and 4I together. This closes the circuit to the plate 55.

Strip I1 is mounted so as to be normally biased to bring contacts 23 and 3| together but is overpowered by spring 49. Spring 49 is proportioned so that it is deflected by the magnetic force oi coil 45 on armature 41 as well as by the snapping of discs 3 and 5 to dotted' line position aided by the bias of strip I1. The normal bias of strip I1 holds contact 23 against contact 3| when discs 3 and 5 snap back to solid line position.

The movement of strip I1 which separated contacts 2| and 21, breaks the circuit to heater 8 so that discs 3 and 5 begin to cool. After a short time they snap back to the solid line position in Fig. 3. Thereupon if for any reason the circuit to the magnetic coll 45 is broken, spring 49 will push armature 41 and post I5 downward to the position shown in Figs. 1 and 2, and the device will be ready to repeat the operation described.

It is generally desirable ilrst to heat the iliament of a cathode tube and after such heating to connect the plate in lts circuit. By means of the relay and cathode tube circuit of the present invention this can be advantageously accomplished. 'Ihe relay described above provides a time delay during which the filament is heated by current in its circuit While the plate circuit is open. After a predetermined time the relay closes the plate circuit and simultaneously closes a holding circuit for itself. Thereupon the device automatically resets and is ready to re-cycle.

In lieu of the ambient compensated thermostatic switch I a simple thermostatic disc (not ambient compensated) may be substituted if the advantages of ambient compensation are not desired.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A time-delay circuit controller for closing a ilrst circuit a substantially predetermined time interval after the closing oi.' a. second circuit, comprising a relay-controlled switch having terminals for connection into the nrst circuit, the relay oi' said switch being connected in a relay circuit, a thermostat, a heater positioned to heat the thermostat and connected in a. heater circuit, a double-throw switch having one of its poles connected in series with the relay in the relay circuit and its other pole connected in series with the heater in the heater circuit, said double-throw switch having a contacter movable between a first position wherein it closes the heater circuit and opens the relay circuit and a second position wherein it closes the relay circuit and opens the heater circuit, said relay and heater circuits having terminals for connection into said second circuit so that they may be energized thereby, said thermostat being positioned to engage the contactor of the double-throw switch and move it from its said ilrst to its said second position upon being heated by the heater, said contactor being 'normally biased to its said second position, and an operating member controlled by the relay and movable in response to deenergization of the relay to a position wherein it engages the contactor and holds the latter in its said nrst position against its bias.

2. A time-delay circuit controller as set forth in claim 1 wherein the thermostat is a snap-acting, automatically resetting thermostat adapted to snap from a normal cold position to a hot position to move the contactor to its said second position upon being heated by the heater, and adapted automatically to snap back to its normal cold position when the heater is deenergized.

3. A time-delay cncuit controller for closing a ilrst circuit a substantially predetermined time interval after the closing oi a second circuit, comprising a base, a. relay-controlled switch mounted on the base having a holding coil connected in a holding circuit, said switch being normally biased open and closing upon energization of the coil, the terminals of the switch being electrically connected to tines on the base for plugging into said ilrst circuit, a thermostat mounted on the base, a heater mounted on the base in position to heat the thermostat and connected in a heater circuit, a double-throw switch mounted on the base having one of its poles in series with the holding coil in the holding circuit and its other pole in series with the heater in the heater circuit, said double-throw switch having a contactor movable between a irst position wherein it closes the heater circuit and opens the holding circuit and a second position wherein it closes the holding circuit and opens the heater circuit, said contactor being normally biased to its said second position, said holding and heater circuits being electrically connected to tlnes on the base for plugging into said second circuit, means on said relay-controlled switch engaging the contactor and holding it in its said first position against its bias when the holding coil is deenergized, said thermostat being positioned to engage said contactor upon being heated by the heater and move it to its said second position against the bias of said relay-controlled switch.

4. A time-delay circuit controller as set forth in claim 3 wherein the thermostat is a snap-act 75 ing, automatically resetting thermostat adapted 5 to snap from a normal cold position to a hot posi- UNITED STAgES PA'I'EN'IB tion to move the contactar to its said second p0- Number sition upon being heated by the heater,' and 1 893 223 B fame Date adapted automatically to snap back to its normal 2005584 ur le Jan' 3' 1933 cold position when the heater 1s deenerglzed. 6 Heyroth June 18' 1935 2,104,844 Alel Jan. 11, 1938 JOIIN Q MOORHEA11 2,228,515 Folllds JBID. 14, 1941 2,256,249 Harris sept. 16, 1941 REFERENCES CITED FOREIGN PATENTS The following references are of record 1n the 10 Number gountry Date le o1' this @utenti 551,786 Germany June 6, 1932 

